Engineering topics
Starr, Gregory
Publications and source records attributed to Starr, Gregory.
AmeriFlux US-EvM Everglades Saltwater intrusion marsh
This is the AmeriFlux version of the carbon flux data for the site US-EvM Everglades Saltwater intrusion marsh. Site Description - This is a site in Southeaster Florida that is experience an ecosystem state shift caused by saltwater flooding. We are seeing sawgrass mortality and mangrove invasion
AmeriFlux FLUXNET-1F US-Elm Everglades (long hydroperiod marsh)
This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Elm Everglades (long hydroperiod marsh). This is the FLUXNET version of the carbon flux data for the site US-Elm Everglades (long hydroperiod marsh) produced by applying the standard ONEFlux (1F) software. Site Description - None supplied.
AmeriFlux FLUXNET-1F US-Esm Everglades (short hydroperiod marsh)
This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Esm Everglades (short hydroperiod marsh). This is the FLUXNET version of the carbon flux data for the site US-Esm Everglades (short hydroperiod marsh) produced by applying the standard ONEFlux (1F) software. Site Description - None supplied.
Biophysical Factors Influence Methane Fluxes in Subtropical Freshwater Wetlands Using Eddy Covariance Methods
Not provided.
Water use in a young Pinus taeda bioenergy plantation: Effect of intensive management on stand evapotranspiration
Abstract The increasing demand for plant‐derived bioenergy is projected to expand tree plantations with intensive silviculture and improved tree genetics. These silvicultural practices result in faster stand development and canopy closure, which may also influence the systems' water dynamics. Here, we studied the evapotranspiration (ET) of a young (5 years old) intensively managed loblolly pine ( Pinus taeda ) stand and investigated the components of ET to determine its contribution to overall water use. We also compared ET with plantations that received less intensive management to determine whether our stand used more water. We used the eddy covariance method to estimate ecosystem‐level total ET (ET EC ), while plot‐level estimates of ET (ET P ) were obtained via soil lysimeters, sap flow sensors, and throughfall collectors, enabling measurement of the components of ET. Soil evaporation (Es) was the largest component of ET P (36%) over the course of the study, while transpiration and canopy interception accounted for 27% and 22%, respectively. Es decreased with stand development, while transpiration and canopy interception increased. Leaf area index (LAI) and precipitation were the most significant factors controlling ET and its components. Compared to previous studies in different sites that have similar age but lower LAI, our stand had higher water use. This high water use in the early stages of stand development was primarily due to high Es before the canopy was fully developed. While there are potential sources of uncertainty when comparing ET EC and the component fluxes in ET P , results from the two methods were not significantly different. This study had the advantage of using multiple methods to understand and verify the component processes that contribute to ET. Therefore, we recommend that multiple measurement techniques be used in the long‐term observation of ET, and in particular for the evaluation of the impact that intensively managed forests have on water resources in the southeastern United States.
Integrating Aquatic Metabolism and Net Ecosystem CO2 Balance in Short- and Long-Hydroperiod Subtropical Freshwater Wetlands
Abstract How aquatic primary productivity influences the carbon (C) sequestering capacity of wetlands is uncertain. We evaluated the magnitude and variability in aquatic C dynamics and compared them to net ecosystem CO 2 exchange (NEE) and ecosystem respiration ( R eco ) rates within calcareous freshwater wetlands in Everglades National Park. We continuously recorded 30-min measurements of dissolved oxygen (DO), water level, water temperature ( T water ), and photosynthetically active radiation (PAR). These measurements were coupled with ecosystem CO 2 fluxes over 5 years (2012–2016) in a long-hydroperiod peat-rich, freshwater marsh and a short-hydroperiod, freshwater marl prairie. Daily net aquatic primary productivity (NAPP) rates indicated both wetlands were generally net heterotrophic. Gross aquatic primary productivity (GAPP) ranged from 0 to − 6.3 g C m −2 day −1 and aquatic respiration ( R Aq ) from 0 to 6.13 g C m −2 day −1 . Nonlinear interactions between water level, T water , and GAPP and R Aq resulted in high variability in NAPP that contributed to NEE. Net aquatic primary productivity accounted for 4–5% of the deviance explained in NEE rates. With respect to the flux magnitude, daily NAPP was a greater proportion of daily NEE at the long-hydroperiod site (mean = 95%) compared to the short-hydroperiod site (mean = 64%). Although we have confirmed the significant contribution of NAPP to NEE in both long- and short-hydroperiod freshwater wetlands, the decoupling of the aquatic and ecosystem fluxes could largely depend on emergent vegetation, the carbonate cycle, and the lateral C flux.
Representativeness of Eddy-Covariance flux footprints for areas surrounding AmeriFlux sites
Not Available
Representativeness of Eddy-Covariance flux footprints for areas surrounding AmeriFlux sites
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AmeriFlux US-LL1 Longleaf Pine - Baker (Mesic site)
This is the AmeriFlux version of the carbon flux data for the site US-LL1 Longleaf Pine - Baker (Mesic site). Site Description - Mesic longleaf pine site with wiregrass in the understory and >90 year old Pinus palustris in the mid- and overstory
AmeriFlux US-LL2 Longleaf Pine - Dubignion (Intermediate site)
This is the AmeriFlux version of the carbon flux data for the site US-LL2 Longleaf Pine - Dubignion (Intermediate site). Site Description - Intermediate longeaf pine site with wiregrass in the understory and >90 year old Pinus palustris and Quercus spp. in the mid- and overstory and Quercus spp.
AmeriFlux US-LL3 Longleaf Pine - Red Dirt (Xeric site)
This is the AmeriFlux version of the carbon flux data for the site US-LL3 Longleaf Pine - Red Dirt (Xeric site). Site Description - Xeric longeaf pine site with wiregrass in the understory and >90 year old Pinus palustris and Quercus spp. in the mid- and overstory